I'm a new research from Brazil who works with T. cacao, if someone likes chocolate so we have something in common. I'm writing a project to develop RAD-Seq markers and I'd like some helps on the budget, can someone help me??

What do you want to know?
Do you know how many cut sites are in the genome? The number of RAD tags will be twice that. Are you planning single-end or paired-end sequencing? Do you want to capture heterozygosity at a high rate (higher read depth needed)?
For a single-end experiment, you might do a rough calculation like:
10 samples * 100,000 tags * 20X coverage * 30% "waste" = 26M reads.
Ordering adapters will add to the cost. Library consumables will be up to $20 per sample, depending on the project. Time... that is usually the driving cost factor, especially for trying it the first time. On both the library prep and analysis side of things.